Great sound, no buzz. But I didn't have any place for the 9v battery so I had to create space with a wood router, put it under the pickguard (without hatch, have to remove the pickguard to change battery).
And note there are different ways to connect this depending on the setup (J, JA and JCS set). My bass has 3 knobs (Vol neck, Vol bridge and Master tone), without selection switch (J-style wiring). That is the first diagram. And only one battery, the extra battery buss not needed.